Artificial reproduction of vimba bream (Vimba vimba) cultured generation F2 and eggs management under controlled conditions

Abstract

The experiments were conducted to investigate the hormonal stimulation of oocyte maturation in cultured (F2 generation) vimba bream (Vimba vimba) under controlled conditions and some aspects of egg management. In artificial reproduction, four hormonal agents (CPH, Ovopel, Ovaprim, and hCG) were tested. Fish were intraperitoneally (IP) injected with two doses of the hormonal agents at the base of the ventral fin. The highest percentage of ovulating vimba bream females (100%) was obtained in the Ovaprim group. Fertilization and hatchability percentages were nearly 95% and 93% in this group. In the control group, which was not injected with hormones, only one female from seven ovulated. Regarding the egg management aspects, the effects of 1) time adding sperm to activated eggs, 2) portional adding sperm to eggs, and 3) pH of the ovarian fluid on fertilization success of vimba bream were also assessed. The results indicate that vimba bream eggs retain fertilization capacity as long as 150–180 s after their activation. When fertilization was carried out within 30 s from the activation of the eggs, the hatchability rate of the larvae was over 80%. The analysis of the results of the present study indicates that there is a statistically significant correlation between vimba bream ovarian fluid pH and the hatching rate of larvae (R2 = 0.954). Moreover, a hatching rate (%) of >50% was noted in the females, of which the ovarian fluid pH was above 7.6. Thus, the results of the present study indicate that the pH of the ovarian fluid is an important factor affecting the quality of vimba bream gametes. The obtained results can be successfully used to produce vimba bream stocking material in a fish farm with the use of cultured spawners.